Shell moderately small to fairly large, claviform with high, acute spire and moderately produced, obliquely truncate base, tip of siphonal canal seldom deeply indented; fasciole usually well-developed in adult; labrum thin, although generally a strong varix preceding it, anal sinus deep, varying in shape, situated on shoulder slope, bordered below by a weakly alate expansion of lip; parietal callus forming a small to massive pad or nodule in posterior angle of aperture, generally constricting entrance to anal canal; subsutural cord more or less strong, shoulder sulcus distinct to deep; axial ribs well-developed, stopping at shoulder; often vividly patterned with brown. Protoconch narrowly domed to conical, 2-5 whorls, smooth, except sometimes for a few weak axial riblets near termination. Operculum oblanceolate with terminal nucleus. Radula crassispirine, marginal plates with relatively short shaft, single somewhat ill-defined cutting edge and long accessory limb.

Diagnosis: Shells small to large, 13 to 57 mm, high spired, solid. Protoconch small, smooth, rounded, 2 whorls. Up to 12 flattened to convex teleoconch whorls. Suture thin, not channeled, may be undulating. Sculpture complex, dominated by axial ribbing which tends to start part way down whorl. Spiral cords of varying strength may be present, often including a strong subsutural cord. Outer lip thickened, often incurved. Sinus deep, U shaped. Callus absent. Columella narrow to medium width, smooth. Aperture deep. Anterior canal short, usually notched. Colour variable, off-white to colourful. Marginal plates of radula with short shaft with long cutting edge (Kilburn, 1989). Indo-Pacific; Recent and fossil at least to the Eocene, shallow water, primarily tropical.
Remarks: Shuto (1965) recognized both Inquisitor and Pseudoinquisitor at the generic level but Powell (1966: 79) concluded Pseudoinquisitor is in fact a synonym of Inquisitor
The genus Ptychobela Thiele, 1925 has been considered by many authors to be a synonym of Inquisitor, but the late Virginia Orr Maes examined the radulae and considered the two genera to be separate, a view followed by Springsteen and Leobrera (1986) and Kilburn (1988). The question was investigated in detail by Kilburn (1989).
Powell (1944) listed 5 species of Inquisitor (as Pseudoinquisitor) from the Miocene of Victoria and Ludbrook (1958) recorded two species from South Australia.
As indicated above, the genus Inquisitor as recognized in this paper has been restricted from the concept of Hedley (1922). There is still considerable shell variation between some of the species. However until the radulae become available for study and related genera are better understood, it seems best not to restrict the genus further.